util: in-memory storage

refs #1940

specification:
http://redmine.named-data.net/projects/ndn-cxx/wiki/InMemoryStorage

Change-Id: I7416d0dac4b4865ad931c3bf83180a043788405b
diff --git a/src/common.hpp b/src/common.hpp
index 9d15e49..ae69686 100644
--- a/src/common.hpp
+++ b/src/common.hpp
@@ -24,6 +24,18 @@
 
 #include "ndn-cxx-config.hpp"
 
+#ifdef NDN_CXX_HAVE_TESTS
+#define VIRTUAL_WITH_TESTS virtual
+#define PUBLIC_WITH_TESTS_ELSE_PROTECTED public
+#define PUBLIC_WITH_TESTS_ELSE_PRIVATE public
+#define PROTECTED_WITH_TESTS_ELSE_PRIVATE protected
+#else
+#define VIRTUAL_WITH_TESTS
+#define PUBLIC_WITH_TESTS_ELSE_PROTECTED protected
+#define PUBLIC_WITH_TESTS_ELSE_PRIVATE private
+#define PROTECTED_WITH_TESTS_ELSE_PRIVATE private
+#endif
+
 #include <stdint.h>
 #include <stddef.h>
 #include <unistd.h>